The physiological process of parturition is, in some sense, everwhere the same. Yet we observe that different cultures have produced strikingly different ways of handling pregnancy, birth, and the pospartum period. It is also the case that the prevalence of infant impairment varies across societies and that our own way of "doing birth" is not correlated with particularly favorable statistics for infant outcome. The proposed project is a first step in a long-range crosscultural study of birth as a physiological process embedded in a sociocultural and interactional context. It relies on social-science methodology, with emphasis on anthropological field studies and interactional analysis in an attempt to specify some of the sociocultural influences on pregnancy outcome which have been inaccessible to strictly biomedical research methodology. Initial fieldwork will be conducted in an indigenous setting, with Maya Indian women in Yucatan, Mexico, as well as in modern obstetric environments in Holland and Sweden. A system-oriented, biosocial, crosscultural framework will be constructed for analyzing birthing systems with the objective of identifying structural characteristics of such systems that have a bearing on pregnancy outcome. This study is expected to contribute to a reduction of pregnancy wastage and to an improvement in the quality of life.